Jo Tetsuma (鉄馬丈, Tetsuma Jō) is a fast and quiet guy, he has a habit of following orders to the letter, and that can lead to disaster. It is very important to give him specific instructions and to watch him carefully. Otherwise, he will follow any general directions to the extreme. For example, the coach once said to him, "Go run a bit!!" so he kept running for 3 days and 3 nights, until he collapsed from hunger. During another incident, Tetsuma was told to wake Kid in five hours while on a flight to the United States, yet ends up bursting out of the back window of a bus to go look for Kid 3 hours later after arriving in Houston! (In this way he is like a golem.) Whenever Kid calls a pass route, he dashes and uses it as followed, no questions asked. This makes him perfect for his position as a Wide Receiver, since the Kid doesn't even have to look for him in order to pass. In spite of his seemingly robotic demeanor, Tetsuma is a nice person, who has been friends with Kid since they were kids.

One important note is that after the game with Deimon, Tetsuma invokes a penalty, by striking Monta when he was about to attack the referee for ruling in favor of Seibu. This was actually done to save Monta from destroying the Devil Bats' chances of playing for third place in the tournament. As a result, Tetsuma was banned from playing in the finals of the Fall Tournament against Oujou. Without him, the Gunmen lost out to the White Knights again, but Monta vows to meet up with Tetsuma again during the Kantou Elimination Tournament. However, this was not to be as the Kid is seriously injured against the Dinosaurs' monstrous lineman Gao. With him gone, Tetsuma loses control of himself and lunges against Gao while providing cover for Riku, proving no match for the massive lineman.

In the last chapter he became one of Deimon's trainers for special training for the Christmas Bowl. He trains Yukimitsu, dragging him behind to increase his speed as well as his stamina. It also serves as physical training for Yukimitsu so he can keeping his pass route tracks in spite of his low physical stats and under hard pressure and teaches him that even if an opponent forces him to go out of the rails his body should come back on the rails and tells him that is the job required for him.

Techniques/Strategies

Pass Routes - Tetsuma has drilled all known pass routes into his head and can run them like a conditioned reflex. All he needs is to hear the route called out by the Kid and he'll perfectly execute the movement. Nothing can disrupt him when he runs his routes, although Monta has made him fumble once.

Trivia

His name also means Iron Horse. In America they used this nickname for the steam-engine train in the old west. This gives meaning to the pass routes he is ordered to follow, which likens him to a train that cannot be altered from the track it runs. He will bowl over anyone who gets in the way on the tracks, even anyone try to stop him in illegal way will found it's near impossible to stop him. In the game against Deimon however, Monta does manage to upset his route and cause him to fumble, by aiming to his fingers, he manages to intercept the pass meant for him. Monta also manages to rip of a ball from his catches by aiming for the seams during Deimon's last Onside Kick, but it was ruled as Seibu's ball due to Tetsuma managing to touch the ground first while keeping his ball.

In a match against the Ojo White Knights, he was the cause of a huge lead 20-7. But because he drank too much water during half-time, he cannot continue as he has to go to the toilet the entire time, causing his team to lose 20-21.

Tetsuma senior, his father, is known for his straight driving habit (that might be inherited by Tetsuma).He will follow every sign, and ensures that his car won't be off less than 10 cm from the street border. If he found a car that parking carelessly in the street, blocking his way, he simply run over the car and used it as a shield.